India rubber spring



Febg25, 1936. A. SPENCER INDIA RUBBER SPRING Filed NOV. 17, 1934 4Sheets-Sheet l Feb. 25, 19136; A. SPENCER 2,032,100

INDIA RUBBER SPRING Filed Nov. '17, 1934 4 Sheets-Sheet 2 H 1 "Mm [WW 137 "9 5 353%; k/ lexajzoler $pe7wez;

Feb. 25, 1936. A. SPENCER INDIA RUBBER SPRING Filed Nov. 17, 1934 4Sheets-Sheet 3 Feb. 25, 1936. A. SPENCER INDIA RUBBER SPRING Filed Noy.17, 1934 4 Sheets-Sheet 4 Spank/e flaw a Patented Feb; 25, 1936 PATENTOFFICE mom RUBBER srnmo Alexander Spencer, Westminster, London,

' England Application November 17, 1934, Serial No. 753,540 In GreatBritain October 29, 1931 23 Claims.

This application is filed as a continuation in part of each of mycopending applications Serial Numbers 619,164, filed June 24, 1932, and667,899, filed April 25, 1933.

This invention relates to India-rubber springs and more especially toIndia-rubber elements of the type disclosed in .my aforesaidapplications for assembly on rigid foundation or supporting plates. Theinvention also relates to units comprising such foundation or supportingplates having the India-rubber elements thereon;

Heretofore, India-rubber springs for bufiing and draft gear and forother purposes have comprised a plurality of' foundation or supportingplates assembled in series with intermediate separating plates, eachsupporting plate having rectangular, oval or annular frames of Indiarubber projecting from its opposite faces. In my Patent No. 1,890,795there is disclosed a spring unit, the India-rubber elements whereof arein the form of straight parallel bars, thereby simplifying the moldsnecessary for the manufacture of spring units and considerablyreducingthe cost of production. When bar-type spring elements of the kindheretofore used are subjected to compression, the relative expansiontransversely of the bar greatly exceeds the corresponding expansion in alongitudinal direction, with the result that such elements undergogreater distortion about their middle portions than at theirextremities, with the result that such middle 1 portions are subject toundue wear and distortion.

A feature of considerable importance in connection with parallel-sidedbar elements is that under compression they attain a maximum transversedimension approximately centrally of the major axis, diminishing towardseach end of the bar, that result being produced by the considerableresistance to longitudinal flow or expansion of the center zones of theelements by the adjoining terminal ends so that the bulk of thedistortion resulting from compression is fixed to take place in atransverse direction, and, as aforementioned, such inherent asymmetry ofbar type elements has the disadvantage that when'such elements areassembled on a supporting plate a mutual support is provided only at thecentral portions of the bars and there is no continuous mutual supportbetween adjacent bars which would obtain should the side walls of theThe primary object of this invention is to overcome the aforesaiddisadvantages and to provide a construction of spring deviceparticularly adapted for bufling and draft gear in which the springelements thereof shall have mutual support on each side for the majorportion of their length so that such elements may give a maximumeifectiveresistance under a predetermined compression and so thatdistribution of stress throughout the body of the elements will be moreuniform and undue wear at the middle portions of the elements isavoided, whereby durability of the spring device is greatly enhanced.

'I'he India-rubber spring elements may be of various shapes and may beof a generally rectangular form, as shown in my aforesaid applicationSerial No. 619,164, or of a generally sectorial form, as shown in myaforesaid application Serial No. 667,899. Whether the elements are ofgenerally rectangular form, or of polygonal form, if they are arrangedadjacent one another on a foundation or supporting plate in a.predetermined relation, the sides thereof, when the elements aresubjected to a predetermined compression, will meet each other in astraight line and provide mutual support throughout the major portion oftheir length. i

. Further and favorable objects will appear from the followingdescription.

According to this invention, the India-rubber spring elements arewaisted or reduced in the middle portion of their length to an extentinsuring that the asymmetric distortion resulting from a predeterminedload will cause the side walls of the bar to lie in a single plane andwhen 3 generally rectangular bar elements are utilized and such elementsare subjected to a predetermined compression, the side walls thereofwill become substantially parallel or equidistant throughout theirlength.

Whether the bar elements are of generally rectangular form or are ofgenerally sectorial for, or of polygonal form the portions thereofprojecting at each face of the supporting foundation or plate may betruncated or pyramidal in form and when the elements are of generallyrectangular or generally sectorial form the ends preferably are madecurviform whereby chafing and deterioration of the corner portions isavoided.

When generally sectorial-shaped elements are used, their wider ends maybe so shaped in the static condition that when the elements aresubjected to a predetermined compression they will describe an arc of acircle, and if the elements are 55 arranged on a circular disk withtheir narrow ends adjacent, the center of the several arcs may be thecenter of the disk. I

When applied to triangular-approximately equilateral-square orrectangular, pentagonal,

o tcthe-element, and further the elimination of I curvilinear junctionsas it were inside theangle's, or preferably by cur-viform protuberancesform-:.

hexagonal and similar polygonal basic shapes of element, the inventionprovides re-entrant sides the sharp anglesbetween adjacent sidesby.'eased ingbosses encircling the angles which provide a greater areaof support for the rubber at these locations and prevent the excessivewear and deterioration which is otherwise likely to occur,

,while simultaneously producing concavity in the side walls so that theequivalent re-entrant contour'is obtained.

Hitherto, where circular lIhdia-rubber elements "have been utilized,irrespect ve f the particular manner of disposition over the area of.the supporting plate-and irrespective of the shape of such plate;connderable wastage of available space betweenadjacent elements is aninherent defect of the circular form but this defect is avoided by thepelygonal form made practicable by this invention, as elements ofpolygonal form may be arranged to interrnesh in the manner of the cellsof a honeycomb. v

. The present invention therefore also comprehends a spring unitconsisting of a metal plate and re entrant-sided polygonal elements ofIn-. F dia-rubber at the faces of the plate so shagd and disposedrelatively to one another that under 'a.

predetermined compression the juxtaposed side a walls of adjacentelements mutually ab-nt and 2 Projecting from each face thereof.

4 improved results obtained on deformation under In the drawings Fig.1.is a perspective view of one embodiment of an India-rubber element.

Fig. 2 is an empiric illustration showing the stress resulting fromreducing or waisting the central portion bf a bar-element of the formshown in Fig. 1.

Fig. 3 is an eievational view of a spring unit comprising a metalsupporting plate having waisted bars disposed thereover in accordancewith the disclosure of my copending application Serial Number 619,165,flied June 24, 1932, Patent No. 2,001,855, May 21, 1935.

Fig. 4 shows apluralityof units of the type shown Fig. 3 assembled on adraw rod with F separating metal plates between adjacent units andadapted for cushioning either buff or draw stresses.

Fig. 5 is arr elevatlonal .view of a spring unit having India-rubberspring elements of generally sectorial form disposed over'a circularsupporting plate.

' Fig. 6 is a cross sectional view ohlinili-S of Fig. 5.

Fig. '7 is a view similar to Fig. 5 showing the use of india rubberspring elements of polygonal form. 1

Fig. 8 is a cross sectional view on line 8-8 of Fig. 7, and

Fig. 9 is an elevaticnal view of a quasi-rectangular spring unit alsoembodying India-rubber spring elements of polygonal form.

Referring now to the drawings, and first to the embodiment of theinvention shown in Figs. 1 to 4.

and more particularly to Figs. 1 and 2, it will be noted that the bars Iwhich are employed as elements for India-rubber spring units, have theirside walls 4 and 5 waisted or reduced so as to have a transverse widthsubstantiallyless than the portions lying adjacent the ends of theelement, and that the'transverse dimensions of the elementsprogressively increase from the central portion of the elements to eachend so that the major transverse dimension is in the immediate vicinityof each end.

As it has been found that in use rapid deterioration of the cornerportions is caused by the high internal stress set up when the bar isdistorted by compression, it is preferable to have the end faces of thebar of generally semi-circular or semi-ehiptical form, as shownat 6 andI, in

which case the major transverse dimensions of the bar, indicated at 8,are located where the circular end faces 6 and join the side walls.

When generally rectangular bar elements are subjected to a predeterminedcompression the'side walls of the bar, owing to a greater resistance toflow in a longitudinal direction of the bar, will become substantiallyparallel to each other, as will be apparent from the dotted showing at9andl0ofFig.2.

Substantial operating advantages accrue from the use of elements havingcenter portions of reduced diameter, while the durability and stabilityof the assembled spfings under compression is greatly; enhanced.

Referring now more particularly to Figs. ,3 and 4, it will be noted thespring units are secured to metal or other rigid. supporting plates l2which comprise the foundation of the spring units which are assembled inseries with metal to the rear of a coupler shank l5 and betweenfollowers l6 and I1 in the draft gear of a railway vehicle. a

The barelements I of from each face of the supporting plate l2 and thecoincident bars on opposite sides ofthe plate are united by India rubberpassing through perforations in the plate as shown at is.

Thebarsmaybedisposed inanyusual orap-. propriate manner about thesurface of the supporting plate l2, although maximum stability anddurability will be obtained if the quadratsd disposition forming thesubject matter of my copending application Serial Number 619,615 isadopted. An example of such a disposition is illustrated in Fig. 3where, as will be seen, the barsare disposed with their major axesnormal to the, adjoining edges of the supporting plate 12. As showninthis figure, each of the bars of the parallel seriesof bars 26 havetheir longitudinal axes disposed normai or at right angles to theadjacent plate edge 2|, a facsimile of the parallel series20being.disposed at the other side of the plate adjace the edge 22 andbein i dicated by reference character 23. Intermediate the" series 2|!and 23, and adjoining the top and bottom edges 24 and 25, respectively,of the plate l2, are two additional parallel series'of India rubberproject spring elements 26 and 21, respectively, having theirlongitudinal axes vertical, that is at rightangl'esto their adjacentplate edges.

Each of the bar elements is of-the waisted section shown in Figs. 1 and2 and have the expansion' characteristics there displayed, the sidewalls assuming the condition of parallelism under a predeterminedcompression, whereby maxirial No. 619,615.

For "certain purposes, as where the supportihg; foundation or plate iscircular, oval, etc., it is preferable that the India-rubber elementsconis obtained due to their opposed side walls coming into contact forsubstantially the full length of the elements when they are subjected toa disposition of the bars illustrated makes full use of the availablesurface of the plate I2 and assures a high degree of stability forreasons fully explained in my said copending application Sestituting'the spring unit and projecting ateach face of the supporting plate shallbe of generally.

sectorial form. Figs. and 6 illustrate elements of such form secured toa circular supporting plate andthe unit thereby formed may be assembledin series with intervening separating plates in the same general manneras the units shown in Figs. 3 and 4 to constitute a spring for 'buflingand draft gear on railway vehicles or for' like purposes.

In Figs. 5 and 6 the India-rubber-elements which are of generallysectorial form are shown as .beingsecured to a circular supporting plate3| having a central aperture 32 sufficiently large to receive a draw baror the like. The generally sectorial blocks are disposed about thesurface of the plate '3! so that their narrower ends are adjacent.Instead of the elements having their side walls disposed in radialplanes when in the static condition, the elements, like the elementshown in Figs. 1 to 4, have their central portions waisted or reduced sothat their side walls assume a radial disposition when the unit issubing plates 3! and elements on opposite faces of the plate are unitedby rubber passing through perforations 35 in the plate. The elements Bilare of substantially uniform depth inthe direction of compression andhave flat compression surfaces 36 in contact with the adjacentseparating plates Bit-and 3 3.

Inasmuch as the transverse dimension of the elements adjacent theirouter ends, as indicated at 38, is much greater than the transversedimension adjacent their inner ends, as indicated at 39, the elementsare formed so that their transverse dimension is not symmetrical as isthe case with the waisted bar type elements shown in Figs. 1 to 4, andthe elements are so formed that the maximum reduction occurs nearertheir outer edge than at the. middle thereof, as is indicated at 60.When the spring elements thus have their side wallsasymmetricallyredueed, the greater deformation under compression at thewider portions of the elements is compensated for and underpredetermined compression the side walls of adjacent element will meeteach other in a straight line as indicated at 4| and thereby mutuallysupport each other.

With sectorial blocks, as well as with generj other thereover along theline 4!. '.tion of the elements to on the supporting plate 3| as shownin Fig. 5 not only provides for maximum mutual support between adjacentelements by ally rectangular elements, it has been found that undue wearand distortion occur at the corner portions, and accordingly, thesidewalls of the elements illustrated in Figs. 5 and 6 are so formed asto prevent a curvilinear outline, the junctions between the'side and endwalls being reduced at 42, 43 and 44 whereby suchzwear' anddeterioration is avoided. Y

The form assumed by the elementsunder compression is clearly illustratedin Fig. 5 where two of the blocks on the upper half of the plate areillustrated in this condition and it will be seen that their side wallshave assumed a substantially radial disposition and mutually supporteach The disposirea'son of their opposed side walls coming into contactfor substantially the full length of the elements, but it also makesfull use of the avail ablesurface of the plate (and assures a highdegree of stability.

It will be understood that the extent of reduc-= tion in the transversedimension of the elements 30 about their middle portions, and theasymmetry of the recesses thereby formed in the side walls of theelements is dependent on the degree of compression at which the sidewalls are rethem to assume a radial disposition. The side walls of theelements illustrated in Fig. 5 will reach the radial disposition and becaused to .2.

mutuallysupport each other along the line Hl under compressions whichreduce their depth by approximately fifty percent. The embodiment ofsecton'al elements illustrated in Fig. 5 also have their circumferentialwall 45 flattened somewhat in the static condition, whereby undercompression it presents asurface d6 substantially concentric with theperiphery of the plate 3!.

Referring more in detail to Fig. 7, the circular metal foundation orsupporting plate 58 is similar to the plate 3! shown in Fig. 5 and has acentral aperture 5! for the passage of a bumng or'draw rod similarto'that shown in Fig. 4. At each face of the plate India-rubber springelements 52 having'fiat compression surfaces 52 project and coincidentelements at opposite faces of the plate are united by India rubberpassing through perforations in the plate in the same manner as is shownin Fig. 6 in connection with the generally sectorial shaped elements. Aplu ralityof units such as those shown in Fig. 7 are adapted to beassembled with intervening plates 38 and 3 5 of the same form as thoseshown in Fig. 6 to constitute a spring or cushion device forbufiing anddraft gear in railway vehicles or for other purposes and when soassembled the flat compression surfaces of the India-rubber elementswill contact with the intermediate separating plates. i

In Fig. 7 a unit having five India-rubber spring elementsprojectingfromeach face of the plate 50 is shown and the several elements have thesame shape and size and are uniformly distributed about the plate in thesame general manner as the generally sectorial elements 35 aredistributed about the plate 3! in Fig. 5. However, in Figs. '7 and 8 thebasic shape of the elements is triangular with the apex of the elementsdisposed adjacent one another 'at or about the center of the plate.

In contradistinction to the elements shown in Fig. 5, the generallytriangular elements of Fig. 7

are substantially symmetrical in form. That is, the outer side or base53 of the triangle is sub- ,stantially equal in extent to-the side orradial walls 54 whereby the basic-shape of the elements are equilateraltriangles and more uniform distribution of stress throughout the body ofthe elements is obtained. For reasons already pointed out in connectionwith the from of ele- 1 ments shown in the preceding figures, thecurviform junctions 55 are formed between the side which have centralcircularapertures.

' Like the side walls oi" the elements shown in the precedingflgures,the side 'wallsof the elementsshown in Fig. 7 are reentrantorcurved inwardly so that under apredetermined com-.

pression" they will assume a substantially planar or radial dispositionasindicated at 55 where the dotted line represents the formwhich theseveral elements assumedv when they are. subjected to a predeterminedpressure applied normal to theflat compression surfaces andfrom thedotted line it will be noted that the form of elements shown in thisfigure also provide the mutual support for one another when the ele-.

ments are placed under compression.

The degree of inward curvature of the side walls 54 of the elements andthe radial spacing between the respective elements will bev dependent onthe compression at which it is desired that mutual support will takeplace, that condition being accelerated by arranging the juxtaposed sidewalls 54 of adjacent elementsin closer.prox-' 'imity whencorrespondingly a small degree of inward curvature is necessary.

The outer or peripheral wall 53 of each element may or may not'be madereentrant depending upon theparticular form of foundation plate which isused. As shown inFig. 7, the peripheral walls 53 are notmade reentrantas a circular foundation plate provides a, greater free 7 space fordistortion at the central portion of said side walls. However, when theperipheral walls are not made reentrant, it is preferable. that theybeso shaped that under a predetermined compression at which the juxtaposedside walls 54 come into contact with each other; as along the line 55,the peripheral walls will be substantially concentric with thecircumfere'nce'56of. the plate as shown in 51. This may be accomplishedby forming the peripheral side walls 53 on a radius somewhat greaterthan the radius of the circular Plate-o that these walls will beflattened rela-- tive to the circumference 55 of the plate.

The symmetrical and substantially equilateral form of the elements 52permits each element to be united to its coincident element. at theopposite face of the foundation plate 50 through three plate apertures53, 59 and 63 disposed adjacent the inner and two outer extremitiesrespectively of the element, and therefore widely distributed over thearea. thereof so as to provide a firm and .secure anchorage. 'A furtheradvantage of such a,os2,1oo I by provided are so located as to bestresist the natural outward thrust occurring when .the compressionexceeds that at which the opposed side walls come into contact. t

- The formation of the elements 52 into substan- 5 tially equilateraltriangles also provides an eifective covering of the supporting plateunder the compression at which the sides of adjacent-elements abut andmutually support each other as is clearly'evidenced by the dotted linesshown on the upper half of the plate in Fig. 7 and from that figure itwill be noted that only a very small portion of the area of the plateadjacent. the central aperture 5| and adjacent the periphery 58 remainsuncovered. 1 i V ,-'Ihe adaptability of the generally sectorial formofelements shown in Fig. 5 or thequasitriangular symmetrical elementsshown in Fig. 7 to supporting plates having shapes other than I circularis exemplified by the embodiment of the invention shown in Fig. 9 wherea plurality of quasi or:generally triangular symmetrical India'- rubberelements are assembled upon' a, quasirectangular supporting plate 62having apertures 83 and 64 for the passage of retaining or centralizingrods. It will be understood that thelunit disclosed in this figurewill constitute one of a plurality of such units which 'will beassembled A in series to form a cushioning device of 9. putting anddraft gear of the type generally indicated in Fig. 4.

The lndia rubber elements 55 shown adjacent the apertures and and theends 65 of'the quasi-rectangular supporting plate 62 of the samecharacteristic form as those shown in Figs.

'Iand 8 and have inwardlycurved opposed side walls 61 and inwardlycurved inner walls 68 adjacent the apertures 83 and 64. However. the

elements 65 differ slightly from the elements 52 shown in Fig. 7 as'theouter sides 59 are also made reentrant, or inwardly curved, whereas theperipheral walls. 53 of the elementstshown. in Figs. 7 and 8 were notmade reentrant.

The elements III, II and I2 disposed in'alternate series along the topand bottom edges 15 and 14 of the plate 62, while retaining the generalcharacteristics of the form of elements shown in Figs. 7*and 8, are morenearly trian'gu larin shape as none of the apices are provided with thedouble curviform wall"68 which those elements and the element 65 have. vf Centrally ofthe plate -62, between the apertures 65 and 54, a waistedbar'element 15 of the the space available between the two elements It 55is insuiilcient in the particular shape of the supporting plate 52illustrated accommodate a symmetrical element similar to the elements 55andIOJIorH, I

Each of the elements 55, )10, H and 12 have three point anchorages orunions to their coincident elements .at the opposite face of the plate62 thereby insuring durabilityand freedom from likelihood ofdisplacement in use. y

The dotted lines shown in' the upper half of 65 Fig. 9 clearly disclosehow the adjacent elements .mutually abut and support each other-whentheIndia-rubber element's are subjected-to a predetermined compression, andalso how mutual contact takes place over substantially the whole of thejuxtaposed side walls of adjacent elements to givemaximum resistance tofurther movement under compression. havin shapes other than thatdisclosed in Mg. 9 are Where non-circular supporting plates form shownin Fig. l is'secured'to the plate as ments which, under stress, assume aform such used, India rubber of other symmetrical shapes and sectionsmay be employed which will best suit the configuration of the plate withwhich the elements are to be associated to form a spring unit wherebyefl'ective covering of substantially the whole of the available area ofthe plate under compression will be assured with maximum mutual supportbetween the several elements, and uniform distribution of stressthroughout the bodies of the elements will be obtained.

Whether generally rectangular, generally sectorial, generally polygonal,or other shaped, India-rubber spring elements or bars are used, it ispreferred to employ elements having waisted or reduced center portions,but it will be appreciated that the invention in its broader aspectcomprehends any formation of India-rubber elethat, when the elements aresuitably arranged upon the carrying plate, the opposed side walls ofadjacent elements may afiord each other mutual support.

I claim:

1. An element for an India-rubber spring com- .prising a solid member ofIndian rubber of substantially uniform depth in the direction ofcompression, said bar having substantially flat compression surfaces andhaving its major axis between said surfaces and substantially parallelthereto, said member having portions adjacent each end ofsaid axis ofgreater transverse dimension than a transverse dimension intermediatesaid end portions, whereby under a predetermined compression the lesserintermediate transverse dimension will be caused to become at leastequal to the transverse dimension of at least one of the end portions.

2. A bar element for an India-rubber spring comprising a solid bar ofIndia-rubber of uniform depth in the direction of compression havingflat compression surfaces and having its major axis between saidsurfaces and parallel thereto with the portion at each end of said axisof greater transverse dimension than its centre portion such that undera predetermined compression the side walls of the element becomesubstantially parallel or equidistant from each other throughout theirlength.

3. An India-rubber spring element comprising a solid bar of India rubberhaving fiat compres sion surfaces with its major axis lying between saidsurfaces and parallel thereto and its side walls curved inwardly in thedirection of its length so that the centre portion of the element is ofsmaller transverse dimensions than the portions at the ends of said axiswhen in a static condition such that under a predetermined compressionthe side walls become substantially parallel or equidistant throughouttheir length.

4. An India-rubber spring element comprising a solid bar of India rubberhaving flat upper and lower compression faces and its major axis lyingbetween said faces and parallel thereto and vertical side walls withcurviform ends said side walls being inwardly curved longitudinally ofthe bar to reduce the transverse dimension of its centre India rubbermoulded to opposite faces thereof,

coincident bars being united through said perforations, said bars beingof uniform depth and in thestatic condition being of reduced transversedimensions about their middle portions such that under a predeterminedcompression opposite side walls become parallel, and said bars beinglocated in parallel juxtaposed relation so that the side walls ofadjacent bars are brought into contact for substantially the wholelength thereof, whereby mutual support of the bars by each other isobtained.

6. An India-rubber spring unit comprising ,a metal plate, perforationsin said plate, bars of India rubber moulded to opposite faces of saidplate, coincident bars being united through said perforations, said barsbeing of reduced transverse dimensions about their middle portions suchthat under a predetermined compression opposite side walls becomeparallel and said bars being located in groups of parallel juxtaposedbars so that the side walls of adjacent bars of each group are broughtinto contact over substantially the whole length of such bars, wherebymutual support of the bars by each other is obtained.

7. An India-rubber spring element of general sectorial form and ofuniform depth in the direc-. tion of compression having flat compressionsurfaces, and its major axis between such surfaces and parallel thereto,with its side walls curved inwardly from the radial in the staticcondition such that under a predetermined compression they assumesubstantially a radial disposition.

, 8. An India-rubber spring element comprising a solid block of generalsectorial form and of uniform depth in the direction of compression withfiat compression surfaces and its major axis between such surfaces andparallel thereto, having its side walls curved inwardly from the radialin the static condition such that under a predetermined compression theyassume substantially a radial disposition, and having curviform wallsjoining its side and end walls whereby the ele ment presents a curviformoutline and stress is more uniformly distributed throughout the body ofthe element.

9. An India-rubber spring unit comprising a metal plate, perforations insaid plate, spring elements of general sectorial form and of uniformdepth in the direction of compression with flat compression surfaces andtheir major axes between such surfaces and parallel thereto, at oppositefaces of said plate, coincident elements being united through saidperforations, said elements being radially disposed to juxtaposedrelation on the plate and having their sidewalls curved inwardly fromthe radial in the static condition such that under a predeterminedcompression their side walls assume substantially a radial dispositionwith the walls of adjacent blocks in contact, thereby providing mutualsupport for all elements of the unit over substantially the whole lengthof eaclr'element.

10. An India-rubber spring element of general sectorial form havingopposed compression surfaces, the sides of said element in the staticcondition having recesses therein, with the recesses extending furtherinwardly at the wider end of the element than at the narrower end,whereby upon a predetermined compression the respective side walls willassume a substantially planar disposition throughout the major portionof their length.

11. An India-rubber spring element of generally sectorial form havingopposed compression surfaces, the sides of said element inthe staticcondition having recesis lesv therein, with the re 10' 7, said elementlying between said parallel surfaces cesses extending further: inwardlyfrom the radial at the outer ends theref than at the inner ends, wherebyupon '9. predetermined compression the side walls assurne asubstantially radial disposition. p

12, An Indiairubber spring element of generally sectorlal form and jofsubstantially uniform compressibility; having substantially parallelopposed ,eompression surfaces, the major axis and substantially parallelthereto, the sides said element in the static condition having m cessestherein, with the recesses extending fur: ther inwardly from theffradial at the outer ends thereof than at the inner ends, whereby underii a predetermined compression the side w'alls as- "pression' thesidewalls assume a substantially rubber elements of generally sectorialform car sume a substantially radial disposition;

13. An India-rubber spring element; of generally sectorial form and ofsubstantially uniform depth and compressibility, having oppoeed com-'pression surfaces, the sides of; said element in the static conditionhaving recefsses therein, with the recesses extending further inwardlyfrom the radial at the outer ends theredf than atthe inner ends, wherebyunder a predetermined comradial disposition, the fnds of said elementbeing curved whereby stress: is more uniformly dis-- tributed throughthe Epdy of the element.

14. A spring-unit coinprising a plate, Indiaried b said plate, said'jelements having opposed co I ssion surfaces; the sides of said elementsin the static cpnditior having recesses therein, with the recessesextending further inwardly at the wider endjof the element than at thenarrower end, whereby under a predetermined compression the respectiveside walls of the elements will agsume a substantially planardisposition throughout a major poiition of their length. i .15. springunit comprising a plate, India..-

rubber; elements of generally sectorial form can ried by? said plate,said elements having oppose-:1

, compression surfaces, the sides of said elements inthe staticcondition, having recesses therein, with the recesses extendin'glfurtherginwardly from the radial at the outer ends thereof than at theinnerends, whereby under a predetermined a compression the side walls ofthe elements as sume a substantially radial disposition,

16. A spring unit comprising a plate, Indiarubber elements ofl'generall; sec'torial form and of substantially uniformQdepth andcompressibility carried bysaidplate, said elements having opposedcompression surfaces, th sides r said elements in the static conditionhving" recesses therein, with the recesses extending lfur ther inwardlyfrom the radial at the outer ends thereof than at the inner ends,the'ends ofsaid elements being curved whereby the elements present acurviform eutline and stress is more uniformly distributed throughoutthe bodies of the elements, the spacing of said elements on the platebeing such that under va predetermined compression the side wallsassumesub'stantially a radial disposition with the walls of adjacentblocks-in contact, thereby providing mutual suppart fer all elements ofthe unit over substantial- 70 ly thefwhole length of each elemen v l7.gl spring unit comprising'a'rigid plate has; ing perforations therein,India-rubber elements of generally sectorial form attached to each 182%aosaioo of the plate, coincident elements being connected by integi'alportions thereof extending through the perforations the, elements havingsubstantially parallelopposed compression surfaces, with the major axesof the elements lying between said ;surfaces and substantially parallelthereto, the sides of said elements in a static condition havingrecesses therein; with the recesses ex.-

tending further inwardly from the radial at the outer ends thereof thanat the inner ends, whereby under a predetermined compression the sidewalls of the elements assume substantially a radial disposition. V

18.:An India-rubber spring elementmomprlsing a substantially equilateralpolygonal body of India rubber having flat compression faces and itsstatic condition, whereby stress is'synimetrically distributedthroughout the body of the element under compression and under apredetermined compression the side walls assume asub-planar Idisposition. g

19.- An India-rubber spring element according v to 18 wherein the areaof support for the India rubber at the junctions between adjacent sidewalls is augmented by curviform protuberances simultaneouslygproducingconcavity in .the side walls and preventmg the excessive wear and side*walls re-entrant' or curved inwardly in-the deterioration otherwiselikely 'tooccur at the junctions therebetween.

20. An India-rubber spring element according -to claim 18 having thebasic shape of an equilateral triangle with the angles between adjacentsides eased by curvilinear junctions, wliemby' symr netricaldistrlbution of stress obtains under compression. g 22 21, AnIndia-rubber spring unit comprising a metal plate having a centralaperture and per- 'forations between said central aperture and theperiphery thereof, and India-rubber spring ele--' ments of generallysectorial form at opposite faces of the plate, coincident elements beingunited by India rubber passing through said p-erforations, the radialwalls ofsaid elements being so shaped in the static condition that undera predetermined compression me side walls of adjacent elements mutuallycontact over substantially the whole of their length, the inner ends ofsaid elements having a doubie. curviform contour with a part thereofreentrant to an extent which, under a predetermined compression, Willicause. i the inner end of the elements to follow approxiportion ,ofreduced transverse dimension. 7;

An India-rubber spring element comprising a harof India rubber 'mouldedandfvulcanized a circumferential groove adapted to interlockingly engagea slotted supporting plate, having ilat upper and lower'substantiallyparhllel compression faces terminating symmetrical.

wedge-shaped compression-bodies of India rubber aboye and below saidgroove and having -curviform ends and its centre portion of reduced,transverse dimension.

SPENCER.

